Studies on the Reactivity of a Labile Tungsten Acetonitrile Complex

点击翻译按钮获取中文摘要

The reactivities of highly reactive complexes cis-Cp^*W(CO)_2(L)Me (1, L=McCN ; 2, L=py) towards a variety of reagents such as isocyanides, thiophenes, hydrosilanes, and hydrido (hydrosilyl) complexes were examined.(1) Acetonitrile complex 1 reacted with isocyanide to give acetonitrile-substitution and CO insertion products, whose ratio varied substantially depending upon the reaction temperature and isocyanide concentration. Its unusually high reactivity to the insertion reaction as an alkyl carbonyl tungsten complex was demonstrated by the facile formation of the insertion product even at-60℃. (2) The reaction of 1 with thiophene resulted in the highly selective α-C-H bond activation to give a 2-thienyl complex. (3) Pyridine complex 2 reacted with primary and secondary silanes to produce base-stabilized hydrido (silylene) complexes via Si-H bond activation and 1, 2-H migration, and the reactivity studies of the silylene complexes with hydrosilanes revealed their novel reactivity to afford silylene exchange products and base-stabilized silyl (silylene) complexes. (4) The reaction of 1 with a hydrido (hydrosilyl) rhenium complex gave a hydrido- and silylene-bridged Re-W heterobimetallic complex, and its photolysis led to intramolecular C-H bond activation to form a novel silenyl-bridged heterobimetallic complex.A molybdenum analogue of 2 was also prepared and subjected to reaction with hydrosilanes to afford base-stabilized hydrido (silylene)molybdenum complexes. The reaction of the silylene complex with a primary silane gave redistribution products of the silane in addition to a base-stabilized silyl (silylene) complex.